1;;; clang-format.el --- Format code using clang-format -*- lexical-binding: t; -*- 2 3;; Keywords: tools, c 4;; Package-Requires: ((cl-lib "0.3")) 5;; SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 7;;; Commentary: 8 9;; This package allows to filter code through clang-format to fix its formatting. 10;; clang-format is a tool that formats C/C++/Obj-C code according to a set of 11;; style options, see <http://clang.llvm.org/docs/ClangFormatStyleOptions.html>. 12;; Note that clang-format 3.4 or newer is required. 13 14;; clang-format.el is available via MELPA and can be installed via 15;; 16;; M-x package-install clang-format 17;; 18;; when ("melpa" . "http://melpa.org/packages/") is included in 19;; `package-archives'. Alternatively, ensure the directory of this 20;; file is in your `load-path' and add 21;; 22;; (require 'clang-format) 23;; 24;; to your .emacs configuration. 25 26;; You may also want to bind `clang-format-region' to a key: 27;; 28;; (global-set-key [C-M-tab] 'clang-format-region) 29 30;;; Code: 31 32(require 'cl-lib) 33(require 'xml) 34 35(defgroup clang-format nil 36 "Format code using clang-format." 37 :group 'tools) 38 39(defcustom clang-format-executable 40 (or (executable-find "clang-format") 41 "clang-format") 42 "Location of the clang-format executable. 43 44A string containing the name or the full path of the executable." 45 :group 'clang-format 46 :type '(file :must-match t) 47 :risky t) 48 49(defcustom clang-format-style nil 50 "Style argument to pass to clang-format. 51 52By default clang-format will load the style configuration from 53a file named .clang-format located in one of the parent directories 54of the buffer." 55 :group 'clang-format 56 :type '(choice (string) (const nil)) 57 :safe #'stringp) 58(make-variable-buffer-local 'clang-format-style) 59 60(defcustom clang-format-fallback-style "none" 61 "Fallback style to pass to clang-format. 62 63This style will be used if clang-format-style is set to \"file\" 64and no .clang-format is found in the directory of the buffer or 65one of parent directories. Set to \"none\" to disable formatting 66in such buffers." 67 :group 'clang-format 68 :type 'string 69 :safe #'stringp) 70(make-variable-buffer-local 'clang-format-fallback-style) 71 72(defun clang-format--extract (xml-node) 73 "Extract replacements and cursor information from XML-NODE." 74 (unless (and (listp xml-node) (eq (xml-node-name xml-node) 'replacements)) 75 (error "Expected <replacements> node")) 76 (let ((nodes (xml-node-children xml-node)) 77 (incomplete-format (xml-get-attribute xml-node 'incomplete_format)) 78 replacements 79 cursor) 80 (dolist (node nodes) 81 (when (listp node) 82 (let* ((children (xml-node-children node)) 83 (text (car children))) 84 (cl-case (xml-node-name node) 85 ('replacement 86 (let* ((offset (xml-get-attribute-or-nil node 'offset)) 87 (length (xml-get-attribute-or-nil node 'length))) 88 (when (or (null offset) (null length)) 89 (error "<replacement> node does not have offset and length attributes")) 90 (when (cdr children) 91 (error "More than one child node in <replacement> node")) 92 93 (setq offset (string-to-number offset)) 94 (setq length (string-to-number length)) 95 (push (list offset length text) replacements))) 96 ('cursor 97 (setq cursor (string-to-number text))))))) 98 99 ;; Sort by decreasing offset, length. 100 (setq replacements (sort (delq nil replacements) 101 (lambda (a b) 102 (or (> (car a) (car b)) 103 (and (= (car a) (car b)) 104 (> (cadr a) (cadr b))))))) 105 106 (list replacements cursor (string= incomplete-format "true")))) 107 108(defun clang-format--replace (offset length &optional text) 109 "Replace the region defined by OFFSET and LENGTH with TEXT. 110OFFSET and LENGTH are measured in bytes, not characters. OFFSET 111is a zero-based file offset, assuming ‘utf-8-unix’ coding." 112 (let ((start (clang-format--filepos-to-bufferpos offset 'exact 'utf-8-unix)) 113 (end (clang-format--filepos-to-bufferpos (+ offset length) 'exact 114 'utf-8-unix))) 115 (goto-char start) 116 (delete-region start end) 117 (when text 118 (insert text)))) 119 120;; ‘bufferpos-to-filepos’ and ‘filepos-to-bufferpos’ are new in Emacs 25.1. 121;; Provide fallbacks for older versions. 122(defalias 'clang-format--bufferpos-to-filepos 123 (if (fboundp 'bufferpos-to-filepos) 124 'bufferpos-to-filepos 125 (lambda (position &optional _quality _coding-system) 126 (1- (position-bytes position))))) 127 128(defalias 'clang-format--filepos-to-bufferpos 129 (if (fboundp 'filepos-to-bufferpos) 130 'filepos-to-bufferpos 131 (lambda (byte &optional _quality _coding-system) 132 (byte-to-position (1+ byte))))) 133 134;;;###autoload 135(defun clang-format-region (start end &optional style assume-file-name) 136 "Use clang-format to format the code between START and END according to STYLE. 137If called interactively uses the region or the current statement if there is no 138no active region. If no STYLE is given uses `clang-format-style'. Use 139ASSUME-FILE-NAME to locate a style config file, if no ASSUME-FILE-NAME is given 140uses the function `buffer-file-name'." 141 (interactive 142 (if (use-region-p) 143 (list (region-beginning) (region-end)) 144 (list (point) (point)))) 145 146 (unless style 147 (setq style clang-format-style)) 148 149 (unless assume-file-name 150 (setq assume-file-name (buffer-file-name (buffer-base-buffer)))) 151 152 (let ((file-start (clang-format--bufferpos-to-filepos start 'approximate 153 'utf-8-unix)) 154 (file-end (clang-format--bufferpos-to-filepos end 'approximate 155 'utf-8-unix)) 156 (cursor (clang-format--bufferpos-to-filepos (point) 'exact 'utf-8-unix)) 157 (temp-buffer (generate-new-buffer " *clang-format-temp*")) 158 (temp-file (make-temp-file "clang-format")) 159 ;; Output is XML, which is always UTF-8. Input encoding should match 160 ;; the encoding used to convert between buffer and file positions, 161 ;; otherwise the offsets calculated above are off. For simplicity, we 162 ;; always use ‘utf-8-unix’ and ignore the buffer coding system. 163 (default-process-coding-system '(utf-8-unix . utf-8-unix))) 164 (unwind-protect 165 (let ((status (apply #'call-process-region 166 nil nil clang-format-executable 167 nil `(,temp-buffer ,temp-file) nil 168 `("-output-replacements-xml" 169 ;; Guard against a nil assume-file-name. 170 ;; If the clang-format option -assume-filename 171 ;; is given a blank string it will crash as per 172 ;; the following bug report 173 ;; https://bugs.llvm.org/show_bug.cgi?id=34667 174 ,@(and assume-file-name 175 (list "-assume-filename" assume-file-name)) 176 ,@(and style (list "-style" style)) 177 "-fallback-style" ,clang-format-fallback-style 178 "-offset" ,(number-to-string file-start) 179 "-length" ,(number-to-string (- file-end file-start)) 180 "-cursor" ,(number-to-string cursor)))) 181 (stderr (with-temp-buffer 182 (unless (zerop (cadr (insert-file-contents temp-file))) 183 (insert ": ")) 184 (buffer-substring-no-properties 185 (point-min) (line-end-position))))) 186 (cond 187 ((stringp status) 188 (error "(clang-format killed by signal %s%s)" status stderr)) 189 ((not (zerop status)) 190 (error "(clang-format failed with code %d%s)" status stderr))) 191 192 (cl-destructuring-bind (replacements cursor incomplete-format) 193 (with-current-buffer temp-buffer 194 (clang-format--extract (car (xml-parse-region)))) 195 (save-excursion 196 (dolist (rpl replacements) 197 (apply #'clang-format--replace rpl))) 198 (when cursor 199 (goto-char (clang-format--filepos-to-bufferpos cursor 'exact 200 'utf-8-unix))) 201 (if incomplete-format 202 (message "(clang-format: incomplete (syntax errors)%s)" stderr) 203 (message "(clang-format: success%s)" stderr)))) 204 (delete-file temp-file) 205 (when (buffer-name temp-buffer) (kill-buffer temp-buffer))))) 206 207;;;###autoload 208(defun clang-format-buffer (&optional style assume-file-name) 209 "Use clang-format to format the current buffer according to STYLE. 210If no STYLE is given uses `clang-format-style'. Use ASSUME-FILE-NAME 211to locate a style config file. If no ASSUME-FILE-NAME is given uses 212the function `buffer-file-name'." 213 (interactive) 214 (clang-format-region (point-min) (point-max) style assume-file-name)) 215 216;;;###autoload 217(defalias 'clang-format 'clang-format-region) 218 219(provide 'clang-format) 220;;; clang-format.el ends here 221